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Oncotarget Sep 2015Most tumors circumvent telomere-length imposed replicative limits through expression of telomerase, the reverse transcriptase that maintains telomere length. Substantial...
Most tumors circumvent telomere-length imposed replicative limits through expression of telomerase, the reverse transcriptase that maintains telomere length. Substantial evidence that AKT activity is required for telomerase activity exists, indicating that AKT inhibitors may also function as telomerase inhibitors. This possibility has not been investigated in a clinical context despite many clinical trials evaluating AKT inhibitors. We tested if Perifosine, an AKT inhibitor in clinical trials, inhibits telomerase activity and telomere maintenance in tissue culture and orthotopic xenograft models as well as in purified CLL samples from a phase II Perifosine clinical trial. We demonstrate that Perifosine inhibits telomerase activity and induces telomere shortening in a wide variety of cell lines in vitro, though there is substantial heterogeneity in long-term responses to Perifosine between cell lines. Perifosine did reduce primary breast cancer orthotopic xenograft tumor size, but did not impact metastatic burden in a statistically significant manner. However, Perifosine reduced telomerase activity in four of six CLL patients evaluated. Two of the patients were treated for four to six months and shortening of the shortest telomeres occurred in both patients' cells. These results indicate that it may be possible to repurpose Perifosine or other AKT pathway inhibitors as a novel approach to targeting telomerase.
Topics: Animals; Breast Neoplasms; Cell Line, Tumor; Clinical Trials, Phase II as Topic; Enzyme Inhibitors; Female; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Mice; Mice, Inbred NOD; Mice, SCID; Neoplasms; Phosphorylcholine; Telomerase; Telomere; Xenograft Model Antitumor Assays
PubMed: 26307677
DOI: 10.18632/oncotarget.5200 -
Pediatric Blood & Cancer Jul 2017The PI3K/AKT/mTOR pathway is aberrantly activated in many pediatric solid tumors including gliomas and medulloblastomas. Preclinical data in a pediatric glioma model...
BACKGROUND
The PI3K/AKT/mTOR pathway is aberrantly activated in many pediatric solid tumors including gliomas and medulloblastomas. Preclinical data in a pediatric glioma model demonstrated that the combination of perifosine (AKT inhibitor) and temsirolimus (mTOR inhibitor) is more potent at inhibiting the axis than either agent alone. We conducted this study to assess pharmacokinetics and identify the maximum tolerated dose for the combination.
PROCEDURE
We performed a standard 3+3 phase I, open-label, dose-escalation study in patients with recurrent/refractory pediatric solid tumors. Four dose levels of perifosine (25-75 mg/m /day) and temsirolimus (25-75 mg/m IV weekly) were investigated.
RESULTS
Twenty-three patients (median age 8.5 years) with brain tumors (diffuse intrinsic pontine glioma [DIPG] n = 8, high-grade glioma n = 6, medulloblastoma n = 2, ependymoma n = 1), neuroblastoma (n = 4), or rhabdomyosarcoma (n = 2) were treated. The combination was generally well tolerated and no dose-limiting toxicity was encountered. The most common grade 3 or 4 toxicities (at least possibly related) were thrombocytopenia (38.1%), neutropenia (23.8%), lymphopenia (23.8%), and hypercholesterolemia (19.0%). Pharmacokinetic findings for temsirolimus were similar to those observed in the temsirolimus single-agent phase II pediatric study and pharmacokinetic findings for perifosine were similar to those in adults. Stable disease was seen in 9 of 11 subjects with DIPG or high-grade glioma; no partial or complete responses were achieved.
CONCLUSIONS
The combination of these AKT and mTOR inhibitors was safe and feasible in patients with recurrent/refractory pediatric solid tumors.
Topics: Adolescent; Antineoplastic Combined Chemotherapy Protocols; Child; Child, Preschool; Dose-Response Relationship, Drug; Female; Humans; Male; Maximum Tolerated Dose; Neoplasm Recurrence, Local; Neoplasms; Phosphorylcholine; Sirolimus; Young Adult
PubMed: 28035748
DOI: 10.1002/pbc.26409 -
Cellular Physiology and Biochemistry :... 2017The alkylphospholipid perifosine is used for the treatment of malignancy. The substance is effective by triggering suicidal tumor cell death or apoptosis. Side effects...
BACKGROUND/AIMS
The alkylphospholipid perifosine is used for the treatment of malignancy. The substance is effective by triggering suicidal tumor cell death or apoptosis. Side effects of perifosine include anemia. At least in theory, perifosine-induced anemia could result from stimulation of suicidal erythrocyte death or eryptosis. Hallmarks of eryptosis are cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Cellular mechanisms participating in the orchestration of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress, increase of ceramide abundance, as well as activation of staurosporine sensitive protein kinase C and/or of SB203580 sensitive p38 kinase. The present study explored, whether perifosine induces eryptosis and, if so, whether its effect involves and/or requires Ca2+ entry, oxidative stress, ceramide and kinase activation.
METHODS
Flow cytometry was employed to quantify phosphatidylserine exposure at the cell surface from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, reactive oxygen species (ROS) abundance from DCFDA dependent fluorescence, and ceramide abundance utilizing specific antibodies. Hemolysis was estimated from hemoglobin concentration in the supernatant.
RESULTS
A 24 hours exposure of human erythrocytes to perifosine (2.5 µg/ml) significantly increased the percentage of annexin-V-binding cells, significantly decreased average forward scatter, significantly increased the percentage of shrunken erythrocytes, and significantly decreased the percentage of swollen erythrocytes. Perifosine significantly increased the percentage of hemolytic erythrocytes. Perifosine significantly increased Fluo3-fluorescence, but decreased DCFDA fluorescence and ceramide abundance. The effect of perifosine on annexin-V-binding was significantly blunted by removal of extracellular Ca2+ and by addition of staurosporine (1 µM), but not by addition of SB203580 (2 µM).
CONCLUSIONS
Perifosine triggers eryptosis, an effect at least in part due to Ca2+ entry and activation of staurosporine sensitive kinases.
Topics: Aniline Compounds; Calcium; Cell Size; Ceramides; Eryptosis; Erythrocyte Membrane; Erythrocytes; Flow Cytometry; Hemolysis; Humans; Imidazoles; Phosphatidylserines; Phosphorylcholine; Pyridines; Reactive Oxygen Species; Staurosporine; Xanthenes
PubMed: 28472790
DOI: 10.1159/000475977 -
Cancer Chemotherapy and Pharmacology May 2015Central nervous system tumors are histologically and biologically heterogeneous. Standard treatment for malignant tumors includes surgery, radiation and chemotherapy,...
PURPOSE
Central nervous system tumors are histologically and biologically heterogeneous. Standard treatment for malignant tumors includes surgery, radiation and chemotherapy, yet surgical resection is not always an option and chemotherapeutic agents have limited benefit. Recent investigations have focused on molecularly targeted therapies aimed at critical tumorigenic pathways. Several tumor types, including high-grade gliomas and pediatric pontine gliomas, exhibit Akt activation. Perifosine, an orally bioavailable, synthetic alkylphospholipid and potent Akt inhibitor, has demonstrated activity in some preclinical models, but absent activity in a genetically engineered mouse model of pontine glioma. We evaluated the plasma and cerebrospinal fluid pharmacokinetics of orally administered perifosine in a non-human primate model to evaluate CNS penetration.
METHODS
Perifosine was administered orally to three adult rhesus monkeys as a single dose of 7.0 mg/kg perifosine. Serial paired plasma and CSF samples were collected for up to 64 days. Perifosine was quantified with a validated HPLC/tandem mass spectrometry assay. Pharmacokinetic parameters were estimated using non-compartmental methods. CSF penetration was calculated from the areas under the concentration-time curves.
RESULTS
Peak plasma concentrations (C max) ranged from 11.7-19.3 µM, and remained >1 µM for >28 days. Time to C max (T max) was 19 h. The median (range) AUCPl was 3148 (2502-4705) µM/h, with a median (range) terminal half-life (t 1/2) of 193 (170-221) h. Plasma clearance was 494 (329-637) mL/h/kg. Peak CSF concentrations were 4.1-10.1 nM (T max 64-235 h). CSF AUCs and t 1/2 were 6358 (2266-7568) nM/h and 277 (146-350) h, respectively. Perifosine concentrations in the CSF remained over nM for >35 days. The mean CSF penetration was 0.16 %.
CONCLUSION
CNS penetration of perifosine after systemic administration is poor. However, levels were measurable in both plasma and CSF for an extended time (>2 months) after a single oral dose.
Topics: Administration, Oral; Animals; Macaca mulatta; Male; Models, Animal; Phosphorylcholine; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt
PubMed: 25740692
DOI: 10.1007/s00280-015-2711-1 -
Molecular Immunology Mar 2023Previously, we revealed a crucial role of 5-HT degradation system (5DS), consisting of 5-HT2A receptor (5-HT2AR), 5-HT synthases and monoamine oxidase A (MAO-A), in...
Myocardial ischemia-reperfusion injury is probably due to the excessive production of mitochondrial ROS caused by the activation of 5-HT degradation system mediated by PAF receptor.
AIM
Previously, we revealed a crucial role of 5-HT degradation system (5DS), consisting of 5-HT2A receptor (5-HT2AR), 5-HT synthases and monoamine oxidase A (MAO-A), in ischemia-reperfusion (IR)-caused organ injury. Whereas, platelet activating factor receptor (PAFR) also mediates myocardial ischemia-reperfusion injury (MIRI). Here, we try to clarify the relationship between 5DS and PAFR in mediating MIRI.
METHODS
H9c2 cell injury and rat MIRI were caused by hypoxia/reoxygenation (H/R) or PAF, and by ligating the left anterior descending coronary artery then untying, respectively. 5-HTR and PAFR antagonists [sarpogrelate hydrochloride (SH) and BN52021], MAO-A, AKT, mTOR and 5-HT synthase inhibitors (clorgyline, perifosine, rapamycin and carbidopa), and gene-silencing PKCε were used in experiments RESULTS: The mitochondrial ROS production, respiratory chain damage, inflammation, apoptosis and myocardial infarction were significantly prevented by BN52021, SH and clorgyline in H/R and PAF-treated cells and in IR myocardium. BN52021 also significantly suppressed the upregulation of PAFR, 5-HTR, 5-HT synthases and MAO-A expression (mRNA and protein), and Gα and PKCε (in plasmalemma) expression induced by H/R, PAF or IR; the effects of SH were similar to that of BN52021 except for no affecting the expression of PAFR and 5-HTR. Gene-silencing PKCε suppressed H/R and PAF-induced upregulation of 5-HT synthases and MAO-A expression in cells; perifosine and rapamycin had not such effects; however, clorgyline suppressed H/R and PAF-induced phosphorylation of AKT and mTOR.
CONCLUSION
MIRI is probably due to PAFR-mediated 5-HTR activation, which further activates PKCε-mediated 5-HT synthesis and degradation, leading to mitochondrial ROS production.
Topics: Animals; Rats; Apoptosis; Clorgyline; Monoamine Oxidase; Myocardial Reperfusion Injury; Platelet Membrane Glycoproteins; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species; Receptors, G-Protein-Coupled; Serotonin; TOR Serine-Threonine Kinases
PubMed: 36682136
DOI: 10.1016/j.molimm.2023.01.004 -
Current Medicinal Chemistry 2017The phosphoinositide 3 kinase AKT mammalian target of rapamycin (PI3K-AKTmTOR) signaling pathway is an important in the aetiology of pancreatic cancer (PC) and is... (Review)
Review
The phosphoinositide 3 kinase AKT mammalian target of rapamycin (PI3K-AKTmTOR) signaling pathway is an important in the aetiology of pancreatic cancer (PC) and is frequently activated in PC. It is then associated with a poorer prognosis. Aberrant activation of this pathway is involved in cell metabolism and survival, cell cycle progression, regulation of apoptosis, protein synthesis, and genomic instability. Several agents have been developed to target the Akt/PI3K pathways, including PI3K inhibitors, (e.g. LY294002, Wortmannin), PI3K/mTOR inhibitors (e.g. BEZ235), or Akt inhibitors (e.g. perifosine, MK2206), which have been tested alone or in combinations with DNA-targeted agents (e.g., gemcitabine and fluorouracil) in pancreatic ductal adenocarcinoma (PDAC). However, due to their unfavorable pharmaceutical activities, toxicity, and crossover inhibition of other lipid and protein kinases, these compounds have not been used in clinical studies. In this review, we focus on the progress in the development of Akt, PI3K and mTOR inhibitors for clinical applications, together with the need for the development of in PDAC and the need for the identification of predictive biomarkers and combination strategies with less toxicity in counteracting the mechanisms of resistance to the therapy.
Topics: Autophagy; Drug Resistance, Neoplasm; Humans; Pancreatic Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Signal Transduction; TOR Serine-Threonine Kinases
PubMed: 28176634
DOI: 10.2174/0929867324666170206142658 -
Biochemical Pharmacology Jan 2018Autophagy is a major protein degradation pathway capable of upholding cellular metabolism under nutrient limiting conditions, making it a valuable resource to highly... (Review)
Review
Autophagy is a major protein degradation pathway capable of upholding cellular metabolism under nutrient limiting conditions, making it a valuable resource to highly proliferating tumour cells. Although the regulatory machinery of the autophagic pathway has been well characterized, accurate modulation of this pathway remains complex in the context of clinical translatability for improved cancer therapies. In particular, the dynamic relationship between the rate of protein degradation through autophagy, i.e. autophagic flux, and the susceptibility of tumours to undergo apoptosis remains largely unclear. Adding to inefficient clinical translation is the lack of measurement techniques that accurately depict autophagic flux. Paradoxically, both increased autophagic flux as well as autophagy inhibition have been shown to sensitize cancer cells to undergo cell death, indicating the highly context dependent nature of this pathway. In this article, we aim to disentangle the role of autophagy modulation in tumour suppression by assessing existing literature in the context of autophagic flux and cellular metabolism at the interface of mitochondrial function. We highlight the urgency to not only assess autophagic flux more accurately, but also to center autophagy manipulation within the unique and inherent metabolic properties of cancer cells. Lastly, we discuss the challenges faced when targeting autophagy in the clinical setting. In doing so, it is hoped that a better understanding of autophagy in cancer therapy is revealed in order to overcome tumour chemoresistance through more controlled autophagy modulation in the future.
Topics: Animals; Antineoplastic Agents; Autophagy; Cell Death; Humans; Neoplasms
PubMed: 29203368
DOI: 10.1016/j.bcp.2017.11.021 -
Journal of Pharmacological Sciences Jul 2020The optimum strategy for heart failure (HF) treatment has yet to be elucidated. This study intended to test the benefit of a combination of valsartan (VAL) and...
The optimum strategy for heart failure (HF) treatment has yet to be elucidated. This study intended to test the benefit of a combination of valsartan (VAL) and perifosine (PER), a specific AKT inhibitor, in protecting against pressure overload induced mouse HF. Mouse were subjected to aortic banding (AB) surgery to establish HF models and then were given vehicle (HF), VAL (50 mg/kg/d), PER (30 mg/kg/d) or combination of VAL and PER for 4 weeks. Mouse with sham surgery treated with VEH were used for control (VEH). VAL or PER treatment could significantly alleviate mouse heart weight, attenuate cardiac fibrosis and improve cardiac function. The combination treatment of VAL and PER presented much better benefit compared with VAL or PER group respectively. PER treatment significantly inhibited AKT/GSK3β/mTORC1 signaling. Besides the classic AT1 inhibition, VAL treatment significantly inhibited MAPK (ERK1/2) signaling. Furthermore, VAL and PER treatment could markedly prevent neonatal rat cardiomyocyte hypertrophy and the activation of neonatal rat cardiac fibroblast. Combination of VAL and PER also presented superior beneficial effects than single treatment of VAL or PER in vitro experiments respectively. This study presented that the combination of valsartan and PER may be a potential treatment for HF prevention.
Topics: Animals; Disease Models, Animal; Drug Therapy, Combination; Glycogen Synthase Kinase 3 beta; Heart Failure; MAP Kinase Signaling System; Male; Mice, Inbred C57BL; Organ Size; Phosphorylcholine; Pressure; Proto-Oncogene Proteins c-akt; Signal Transduction; Valsartan
PubMed: 32414690
DOI: 10.1016/j.jphs.2020.04.001 -
Journal of Pain Research 2021Recent studies indicated that analgesic overuse upregulated 5-hydroxytryptamine receptor 2A (5-HTR) and subsequently activated nitric oxide synthase (NOS) and thus...
BACKGROUND
Recent studies indicated that analgesic overuse upregulated 5-hydroxytryptamine receptor 2A (5-HTR) and subsequently activated nitric oxide synthase (NOS) and thus induced latent sensitization, which provided a mechanistic basis for medication-overuse headache (MOH). Moreover, glycogen synthase kinase-3β (GSK-3β) was regulated by serotonin receptors and the phosphorylation of GSK-3β affected NOS activity, indicating that GSK-3β could be involved in the regulation of NOS activity by 5-HTR in MOH pathophysiology. Herein, we performed this study to investigate the role of 5-HTR in MOH pathophysiology and the role of GSK-3β in the regulation of NOS activity by 5-HTR.
MATERIALS AND METHODS
Wistar rats were daily administered with paracetamol (200 mg/kg) for 30 days to set animal models for pre-clinical MOH research. After the rat MOH models were successfully established, the expression of 5-HTR and NOS, GSK-3β activity in trigeminal nucleus caudalis (TNC) were assayed. Then, 5-HTR antagonist ketanserin and agonist DOI were applied to investigate the effect of 5-HTR on NOS activity in TNC of MOH rats, and GSK-3β antagonist LiCl and agonist perifosine were applied to explore the role of GSK-3β in the activation of NOS by 5-HTR.
RESULTS
We found that the expression of 5-HTR and NOS, GSK-3β activity were enhanced in TNC of MOH rats. 5-HTR modulator regulated the activity of NOS and GSK-3β in TNC of MOH rats, and drugs acting on GSK-3β affected NOS activity.
CONCLUSION
These data suggest that GSK-3β may mediate the activation of NOS by 5-HTR and underline the role of 5-HTR in MOH pathophysiology.
PubMed: 33623427
DOI: 10.2147/JPR.S283734 -
Molecular Psychiatry Nov 2023PTEN germline mutations account for ~0.2-1% of all autism spectrum disorder (ASD) cases, as well as ~17% of ASD patients with macrocephaly, making it one of the top...
PTEN germline mutations account for ~0.2-1% of all autism spectrum disorder (ASD) cases, as well as ~17% of ASD patients with macrocephaly, making it one of the top ASD-associated risk genes. Individuals with germline PTEN mutations receive the molecular diagnosis of PTEN Hamartoma Tumor Syndrome (PHTS), an inherited cancer predisposition syndrome, about 20-23% of whom are diagnosed with ASD. We generated forebrain organoid cultures from gene-edited isogenic human induced pluripotent stem cells (hiPSCs) harboring a PTEN (ASD) or PTEN (cancer) mutant allele to model how these mutations interrupt neurodevelopmental processes. Here, we show that the PTEN allele disrupts early neuroectoderm formation during the first several days of organoid generation, and results in deficient electrophysiology. While organoids generated from PTEN hiPSCs remained morphologically similar to wild-type organoids during this early stage in development, we observed disrupted neuronal differentiation, radial glia positioning, and cortical layering in both PTEN-mutant organoids at the later stage of 72+ days of development. Perifosine, an AKT inhibitor, reduced over-activated AKT and partially corrected the abnormalities in cellular organization observed in PTEN organoids. Single cell RNAseq analyses on early-stage organoids revealed that genes related to neural cell fate were decreased in PTEN mutant organoids, and AKT inhibition was capable of upregulating gene signatures related to neuronal cell fate and CNS maturation pathways. These findings demonstrate that different PTEN missense mutations can have a profound impact on neurodevelopment at diverse stages which in turn may predispose PHTS individuals to ASD. Further study will shed light on ways to mitigate pathological impact of PTEN mutants on neurodevelopment by stage-specific manipulation of downstream PTEN signaling components.
PubMed: 38030818
DOI: 10.1038/s41380-023-02325-3